What is a Content Security Policy (CSP) and Why You Need One

Learn how to prevent Cross-Site Scripting (XSS) and other injection attacks by implementing a robust Content Security Policy on your website.


Preventing XSS with Content Security Policy

Content Security Policy (CSP) is a powerful security layer that helps detect and mitigate certain types of attacks, including Cross-Site Scripting (XSS) and data injection attacks. These attacks are used for everything from data theft to site defacement and malware distribution.

How CSP Works

At its core, a CSP tells the browser which sources of content are trusted. Instead of blindly executing any script or loading any image the server sends, the browser checks the CSP header first. If a resource isn't on the "whitelist," the browser blocks it.

Why You Need One

1. **Stop XSS in its Tracks**: Even if an attacker finds a way to inject a `